MIME-Version: 1.0
Server: CERN/3.0
Date: Tuesday, 07-Jan-97 15:56:04 GMT
Content-Type: text/html
Content-Length: 2000
Last-Modified: Monday, 11-Dec-95 16:42:34 GMT

<title>The ACCEL Abductive Reasoning System</title>

<h1>ACCEL</h1>
<br>
ACCEL is a general purpose system that uses abductive reasoning to
construct explanations for observed intelligent phenomena.  These
explanations are then used to avoid redundant work in future problem
solving episodes.  We define an abductive explanation as a consistent
set of assumptions which when combined with background knowledge,
logically entails a set of observations. <p>

ACCEL has been constructed as a domain-independent system, in which
knowledge about a variety of domains has been uniformly encoded as
first-order Horn-clause axioms.  A general-purpose abduction
algorithm, AAA, is used to efficiently construct explanations by
caching partial explanations.  ACCEL has been shown to achieve more
than an order of magnitude speedup in run time for a variety of
domains, including plan recognition in text understanding, and
diagnosis of medical diseases, logic circuits, and dynamic
systems. <p>


Common Lisp source code for the ACCEL system and several diagnosis
domains is available via <!WA0><!WA0><a href="ftp://ftp.cs.utexas.edu/pub/mooney/accel"> 
anonymous FTP </a>. <p>

A more detailed description of this system can be found in the
following publications: <p>

<ol>
<li>  Hwee Tou Ng and Raymond Mooney, "Abductive Plan Recognition and Diagnosis: 
  A Comprehensive Empirical Evaluation," <cite>Proceedings of the Third International 
  Conference on Principles of Knowledge Representation and Reasoning</cite> (KR-92), 
  pp. 499-508, Cambridge, MA, October 1992. 
<li>  Hwee Tou Ng and Raymond Mooney, "An Efficient First-Order Horn-Clause Abduction 
  System Based on the ATMS," <cite>Proceedings of the Ninth National Conference on
  Artificial Intelligence</cite>, pages 494-499, Anaheim, CA, July 1991. 
</ol>

Poniters to these and other related papers can be found on our <!WA1><!WA1><a
href="http://www.cs.utexas.edu/users/ml/abduction.html">Abduction</a> research page.<p>

<hr>
<address><!WA2><!WA2><a href="http://www.cs.utexas.edu/users/estlin/">estlin@cs.utexas.edu</a></address>
